A molecule of sulphur may be represented as

The study of diple moment of a molecule is useful to explain the shape of a molecule and also to predict a The net dipole moment of a polyatomic molecule is the resltant of the different bond moments present in that molecule . The values are generalluy expressed in Debye or in the S.I. units in terms of Coulomb meter (C m) Which our of the following will have maximum dipole moment ?

Polar covalent molecules exhibit dipole moment. Dipole moment is equal to the product of charge separation, q and the bond length d for the bond. Unit of dipole moment is Debye. One Debye is equal to 10^(-18) esu-cm. Dipole moment is a vector quantity. It has both magnitude and direction. Hence, dipole moment of a molecule depends upon the relative orientation of the bond dipoles, but not on the polarity of bonds alone. A symmetrical structure shows zero dipole moment. Thus, dipole moment helps to predict the geometry of a molecules. Dipole moment values can be used to disinguisd between cis- and trans- isomers, ortho-, meta - and para - forms of a substance, etc. The dipole moment value of H-X molecule is 1.2 Debye. If the internuclear distance between H-X is 0.8Å then the % ionic character in H-X molecules is :